This invention relates to pliers, and more particularly, to self-adjusting pliers which also lock with a strong clamping force on an object.
Self-adjusting or auto-adjusting pliers are commonly found on the market. Such pliers have jaws which are self-adjusting accordingly to the size of the work piece to be grasped between the jaws. Examples of such self-adjusting pliers are disclosed in U.S. Pat. No. 6,065,376 and U.S. Pat. No. 6,279,431.
Also commonly found on the market are locking pliers which incorporate a compound toggle locking mechanism or linkage whereby when the moveable jaw of the plier is adjusted to seize a work piece firmly between the moveable and the fixed jaw and the handles are tightly compressed, the toggle mechanism locks the hand tool onto the work piece. Examples of this type of plier are disclosed in U.S. Pat. No. 5,056,385 (a locking plier sold under the trademark VISE-GRIP) and U.S. Pat. No. 6,227,080.
However, in spite of continuous efforts in this field, no one has been able to design practical and truly functional pliers which are both self-adjusting and locking. It is a principal object of the present invention to provide such self-adjusting locking pliers which are easy to operate, fully functional and inexpensive to manufacture.